Neptune's Predominantly Blue Appearance Is Caused by

Neptune's predominantly blue appearance is caused by

A) preferential scattering away from the planet of the blue end of the solar spectrum, in a similar process to that operating in Earth's atmosphere.
B) auroral emissions caused by solar wind particles exciting the atoms and molecules in Neptune's high atmosphere.
C) the fact that solar light has lost much of its red light by scattering in the interplanetary medium at the distance of Neptune.
D) absorption of the red end of the spectrum of reflected sunlight by the methane in its atmosphere.